Strongyloides stercoralis is a nematode parasite which causes a protracted asymptomatic intestinal infection. It is considered a life threatening condition in immunocompromised patients when hyperinfection is associated with disseminated disease. The diagnosis by routine stool examination is very limited since the larval output in stools is very low. We present the case of a 52 year-old Omani man from Salalah, in the southern region of Oman, with a 15-year history of type 2 diabetes mellitus and recently discovered to have hairy cell leukaemia, who complained of nausea, abdominal pain, loss of appetite and loss of weight. An oesophagogastroduodoscopic biopsy was obtained and histopathologic examination revealed gastrointestinal strongyloidiasis.